Distributed-Ledger

Work in progress on a project to create a Distributed Ledger over HTTP in Java. No extra frameworks.

Part One still Todo:

• Refactor the HTTP server Get/Post methods/classes. -- Done

• Fix URLConnection hanging. -- Done

• Rewrite Main Method to better reflect server/client creation. -- Done

• Create a handler for the BlockChain. -- Done

• Create and hash the Blocks within the blockchain. -- Done

  Part One Bugs/Improvements.

  • Bug: If a known Peer is offline and the /block handler is used, each unsuccessful UrlConnection creates its own Block
  • Improvement: The Send/Receiver parts for Block/Transaction are basically the same. Should be easy to refactor them into a more overarching methods.
  • Improvement: Clean up code.

Part Two Readme In Progress:

• Continue to build the entire Ledger.
• Implement the Merkle Tree for blocks.
• TBD.

Guide:

• For each activation of the main class, you get the option to:

  • Write 'y' and enter port for a Standalone Node.
  • Write 'n', enter the IP you want to connect to and the port for the Node that establishes a connection from the start.

• 'IP:Port/getPeers' --> prints out the specific Node/Peers known IP/Port combinations.

• 'IP:Port/getblocks' -->getter that prints out all known Blocks for the specific Node/Peer.(Getter is without arguments)

  • prints out all known Blocks starting from a specific Block.(Getter with arguments).

  • Example: '192.168.1.121:9000/getblocks?blockId=Block_Hex_Value'

• 'IP:Port/getdata' -- getter that requires arguments. Finds specific Block and prints out its content in JSON format.

  • Example: '192.168.1.121:9000/getdata?blockId=Block_Hex_Value'

• 'IP:Port/block' -- Handler that sends a message to the Node to assemble and send out a Block to all known peers.

  • If a receiver Peer does not have the Block, it will starts its own UrlConnection to its known Peers.

• 'IP:Port/transaction' -- Handler that sends a message to the Node to assemble and send out a Transaction to all known peers.

  • If a receiver Peer does not have the Transaction, it will starts its own UrlConnection to its known Peers.

Authors

• Risto Roosipuu - Initial Creator - RistoRoosipuu

License

This project is licensed under the MIT license - see the LICENSE.md file for details.

Acknowledgments

• HTTP Client/Server based on https://www.codeproject.com/Tips/1040097/Create-a-Simple-Web-Server-in-Java-HTTP-Server
• This project uses Gson https://github.com/google/gson